Crystallization features and physico-chemical properties of alkali and alkaline aluminoborate glass–ceramics

2017 ◽  
Vol 53 (2) ◽  
pp. 953-961 ◽  
Author(s):  
S. M. Salman ◽  
S. N. Salama ◽  
H. A. Abo-Mosallam
Keyword(s):  
Glass Ceramics ◽  
Chemical Properties ◽  
Physico Chemical ◽  
Aluminoborate Glass

scholarly journals Physico-chemical properties and structural transformations in the synthesis of boroalumosilicate glass-crystal materials

2021 ◽  
pp. 3-8
Keyword(s):  
Crystallization Process ◽  
Glassy Phase ◽  
Glass Ceramics ◽  
Chemical Properties ◽  
Glass Crystallization ◽  
Crystalline Materials ◽  
Thermophysical Parameters ◽  
Physico Chemical ◽  
Glass Crystal ◽  
Stage Heat Treatment

The aim of this work is to study the areas of glass formation and metastable liquation of the pseudo-ternary system (MgO·Al2O3)-B2O3-SiO2, and study of the crystallization process of glasses of cordierite composition. The crystallization process of glasses of cordierite composition containing B2O3 by a single-stage heat treatment at 1000 oC and 1200 oC, the nature of crystallization, the thermal properties of glasses and glass crystalline materials of the system (MgO·Al2O3)-B2O3-SiO2 were studied. It revealed that during the isolation of a boron-containing solid solution, the residual glassy phase enriched with oxides of MgO and Al2O3, which lead to an increase in the thermal expansion coefficient of the glass phase. The research results provide possibility to synthesize glass-ceramics with certain thermophysical parameters by stopping further glass crystallization at the stage of formation of a certain amount and ratio of the required crystalline and glassy phases.

Calcium Phosphate Materials in Restorative Dentistry: a Review

1988 ◽  
Vol 2 (1) ◽  
pp. 164-180 ◽  
Author(s):  
R.Z. Legeros
Keyword(s):  
Calcium Phosphate ◽  
Polymer Composites ◽  
Glass Ceramics ◽  
Chemical Properties ◽  
Current Status ◽  
Medical Applications ◽  
Restorative Dentistry ◽  
Calcium Phosphate Cements ◽  
Physico Chemical

This report deals with some of the calcium phosphate materials which are currently used in preventive and restorative dentistry and other calcium phosphate materials which have potential for dental and medical applications. Such materials include those which form calcium phosphate in situ (e.g., Bioglass ceramics and calcium phosphate cements) and those originating from natural materials (such as corals and bones). The reports on the development and current status of the calcium phosphate ceramics and glass ceramics presented here were based on recent reviews and recent evaluations of clinical studies for the period 1975 to 1986 (Table 3) with humans and with animals when reports on human studies were not yet available. Methods of preparation and relevant physico-chemical properties of some of the calcium phosphate materials were based on data reported in the literature and on other studies by the author. New calcium phosphate materials, e.g., calcium phosphate cements, calcium phosphate-coated implants, calcium phosphate/polymer composites, have also been briefly covered in this report. Based on the information summarized in Tables 1 to 6 and on solicited comments from clinicians and researchers involved with calcium phosphate materials, several areas of basic and clinical research are recommended (Table 7).

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Physico-Chemical Properties of Recombinant Desulphatohirudin

1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Alpha Helix ◽  
Apparent Molecular Weight ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Recombinant Hirudin ◽  
Physico Chemical ◽  
Recombinant Molecule

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)

Physico-chemical properties of the rare-earth metals, scandium, and yttrium

1963 ◽  
Vol 79 (2) ◽  
pp. 263-293 ◽  
Author(s):  
E.M. Savitskii ◽  
V.F. Terekhova ◽  
O.P. Naumkin
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Chemical Properties ◽  
Physico Chemical ◽  
The Rare Earth

Physico chemical properties and gas adsorption separation characteristics of Itaya zeolite and its modified products.

1990 ◽  
Vol 39 (442) ◽  
pp. 996-1000 ◽  
Author(s):  
Ayao TAKASAKA ◽  
Hideyuki NEMOTO ◽  
Hirohiko KONO ◽  
Yoshihiro MATSUDA
Keyword(s):  
Gas Adsorption ◽  
Chemical Properties ◽  
Physico Chemical
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